At least 50,000 businesses accept bitcoin, a peer-to-peer digital currency invented only six years ago. Are they crazy? Adam White, a former U.S. Air Force captain and Harvard MBA, doesn't think so. He traveled cross-country to Washington, D.C., to tell members of Congress Wednesday how his San Francisco-based company is helping small businesses take advantage of the opportunities created by bitcoin.

White's mission: To explain to Congress how accepting bitcoin payments can "level the playing field for small businesses" and talk about how to "intelligently create policy" concerning bitcoin "without stifling innovation."

• Much lower transaction fees than those charged for credit card or debit card purchases.

• Protection from fraudulent chargebacks since all bitcoin purchases are final.

• Opportunity to easily accept payments from customers anywhere in the world because of bitcoin's borderless, global nature.

Bitcoin's risks:

• It is not legal tender, and there are no laws requiring businesses or individuals to accept bitcoin as a form of payment. If it's suddenly not accepted, "Bitcoin will become worthless," said Mark Williams, a banking, commodities and risk management expert on Boston University's finance faculty.

• Its value is highly volatile -- it's now trading at around $450, compared with more than $1,100 when it peaked in November. A small business that accepts bitcoin "could see profit margins reduced or completely erased in a matter of days."

How Coinbase mitigates this risk: Nearly all of Coinbase's business customers don't hold bitcoins; they exchange them for dollars with Coinbase. Coinbase then sells bitcoins to consumers.

Is Coinbase itself a risky venture? Williams thinks so. He's concerned that the market for bitcoin risk-mitigation services is too concentrated in Coinbase and one other company, BitPay, and their risk of exposure to bitcoin price swings will grow as their number of small business customers increase. A big decline in bitcoin prices "could be financially devastating" to these companies, he said.

Coinbase's response: The company doesn't hold many bitcoins; it sells them to consumers. Plus, the bitcoin world is only entering its "second inning," White said, and bitcoin firms that aren't professionally managed are going out of business. Coinbase, he said, is backed by $31 million in venture capital, and was co-founded by a a former Goldman Sachs trader and a software engineer who is a fraud prevention specialist. White expects new competition "will be standing up" as the industry matures.